The prevalence and incidence of reported gonorrhea has doubled in the last 10 years, indicating that treatment of symptomatic patients with antibiotics as a control measure has failed. It has been proposed that a serologic test to detect asymptomatic females would help in control of the disease. One of the purposes of this research is to determine whether asymptomatic infected females have a serum antibody response to N. gonorrhea. A more effective means of controlling gonorrhea would be the use of a vaccine, and toward this end we intend to use the following approach. There is evidence, based on a study of experimental gonococcal urethritis that males with a history of previous gonorrhea have a lesser incidence of gonococcal urethritis than do those without such a history. We propose to evaluate whether one can identify a population of males who are specifically resistant to gonorrhea by comparing the incidence of gonorrhea among males with (experimental group) and without (control group) a previous history of gonococcal urethritis. By comparing the anti-gonococcal responses of the control and the experimental group we hope to identify immune humoral or cellular components which correlate with resistance to disease. If this component and its antigen were known, one could then rationally attempt to mimic the immunity which follows natural infection in some persons with an immunization procedure.